Composites useful in the making of belts, tires and the like must be extremely cohesive and retain their tensile strength in use. Previous composites have yet to provide ideal retention of tensile strength and cohesive strength. This is especially true in composites including fiberglass cord bonded to durable rubbers which are low in unsaturation like peroxide cured and Zeon Super Composite (ZSC) reinforced hydrogenated nitrile elastomers (HNBR). Accordingly, there is a need for improved composites. ZSC is a zinc acrylate reinforced HNBR available from Zeon chemicals.
U.S. Pat. No. 4,051,281, herein incorporated by reference in its entirety, is directed to an aqueous alkaline dispersion of a rubbery vinyl pyridine copolymer, trimethylol phenol, and a resorcinol compound, in certain amounts, useful in forming an adhesive for bonding glass fiber reinforcing elements or cords to rubber compounds or stocks. After dipping the glass fiber cord in the one-step adhesive dip, the coated cord is heated to dry it and heat cure or heat set the adhesive on the cord. Thereafter, the adhesive containing glass fiber cord is combined or laminated (calendered) with a curable rubber compound and the resulting assembly is cured to form a composite in which the glass fiber cord is bonded to the rubber by means of the adhesive.
British Patent Publication No. 2 155 488 ("the British Patent Publication") discloses adhesive compositions including as essential ingredients 2,3 dihalo-1,3-butadiene polymer, an aromatic nitroso compound, a lead salt of phosphorous acid or of dicarboxylic acids, and at least one maleimide compound. With respect to the essential components of the adhesive components of the British Patent Publication, the aromatic nitroso component will be present in the range from 1 to 200, preferably 10 to 100 parts by weight; the lead salt will be present in an amount in the range form 10 to 200, preferably 25 to 100, and most preferably 35 to 75, pats by weight. The maleimide component will be present in an amount of 0.5 to 100, preferably 2 to 50 parts by weight; with the amounts of each component being on a basis of 100 parts of 2,3-dihalo-1,3 butadiene polymer. The British Patent Publication also states that the use of maleimide compound at 150-200 parts by weight will exhibit better environmental resistance than at 25-75 parts by weight by weight but the resulting increased cost negates its use at the higher levels except in particularly aggressive environments, where cost is a lesser factor.
U.S. Pat. No. 4,119,587 discloses compositions comprising at least one halogen-containing polymer, at least one aromatic nitroso compound, at least one salt of certain inorganic and organic acids, and, optionally, at least one maleimide compound. The claims of the patent describe the use of from zero to about 25 parts by weight, per 100 parts by weight of the halogen-containing polyolefin. The halogen-containing polymers disclosed include chlorosulfonated polyethylene and chlorinated natural rubber.
U.S. Pat. No. 5,268,404 describes adhesives including a halogenated polyolefin, an aromatic nitroso compound, metal oxide such as zinc oxide or magnesium oxide, and optionally a vulcanizing agent such as sulfur or selenium, a phenolic epoxy resin, or carbon black. The use of maleimides in amounts of 0 to 50 parts by weight per 100 parts of polyolefin is also discussed.
Copending U.S. application Ser. No. 08/889,294 filed Jul. 8, 1997 relates to an aqueous adhesive including halobutadiene homopolymer latex, aqueous soluble or dispersible phenolic resin and maleimide-based compound. The maleimide-based compound is present in the adhesive composition in an amount of 10 to 35, preferably 10 to 20, percent dry weight based on the primary components of the adhesive composition.
Accordingly, it is an object of the present invention to provide improved composite materials useful in making belts, tires and the like that include fiber reinforced nitrogen containing rubbers.
It is further an object of the present invention to provide an adhesive useful in bonding rubbers low in unsaturation with various substrates including fibers, cloth, or metal.